Optical disc audio reproduction device having track playback monitoring system

ABSTRACT

Apparatus and method for monitoring audio track playbacks by an optical disc audio reproduction device. A track number corresponding to an audio track encoded on an optical disc is selected to initiate playback of the selected audio track and a corresponding track number is stored in a first memory device. A series of data frames, each having an audio data block and a non-audio subcode block containing a single Q data bit, which define the selected audio track are then read from the optical disc. The data frames are transmitted to a demodulator circuit where the non-audio subcode block is separated from the audio data block. The non-audio subcode block is then transmitted to a microprocessor where the single bit of Q data subcode from each frame is assembled into a Q data subcode block. A portion of the Q data subcode block which contains a UPC code identifying the optical disc is transmitted to a second memory device. The contents of the first and second memory device are then combined in a third memory device to provide a record of audio track playbacks performed by the optical disc audio reproduction device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an optical disc audio reproduction device,commonly referred to as a compact disc (or "CD") player and, moreparticularly, to a CD player having a track playback monitoring systemfor providing a record of the tracks played by the CD player.

2. Description of Related Art

Owners and/or operators of audio reproduction devices, particularlythose in commercial settings, often need to compile a list of soundrecordings 15 replayed by their audio reproduction devices. Onceassembled, such lists may be used for a variety of purposes. Forexample, the assembled listing may be used by a radio station to monitoradherence to the station's "playlist" which identifies sound recordingsselected by the station for public broadcast and may also include arotation frequency indicating how often each of the sound recordings onthe playlist should be broadcast. As programming becomes moresophisticated, the playlist may be subdivided into sub-groups of themaster list, each sub-group being selected for broadcast at a differentfrequency. For example, a first sub-group of sound recordings may bescheduled for broadcast 4-6 times a day while a second sub-group isscheduled for broadcast once a day. Thus, as playlists become moresophisticated, the ability to monitor playbacks broadcast by the stationbecomes of increasing importance.

Another example of an audio reproduction device used in a commercialsetting where the ability to monitor the number of playbacks of soundrecordings performed by the audio reproduction device desirable is the"juke box". A juke- box is a coin operated, audio reproduction device,typically located in restaurants and bars, in which upon payment of adesignated fee, a patron selects, from a list of sound recordings, aparticular recording or recordings for playback. By being able tomonitor the number of playbacks of each listed sound recording, theowner of the juke box would be able to replace infrequently selectedrecordings with more popular selections, thereby enhancing revenuegenerated by the juke box.

One area where the ability to monitor the number of playbacks of soundrecordings by a commercial audio reproduction device is particularlyuseful involves the determination of royalties owed in connection with areproduction of a copyrighted sound recording. The copyright lawsrequire any person who uses an audio reproduction device to reproduce acopyrighted sound recording, either in a fixed tangible medium or in apublic performance or other public broadcast must pay royalties to theowner of the copyrighted sound recording. While some royalty paymentsmay be covered by various compulsory or other licensing arrangements,depending on the circumstances surrounding the reproduction of thecopyrighted sound recording, there may still be a need to accuratelyidentify the particular copyrighted sound recordings reproduced by theaudio reproduction device in order to calculate the amount of royaltiesowed to the owners of the sound recordings.

Various audio reproduction devices which permit a consumer to selectsound recordings for transfer to a tangible, fixed medium, such as acassette tape, which is then sold to the consumer, have been disclosedin the art. For example, U.S. Pat. Nos. 3,990,710 to Hughes, 4,108,365to Hughes, 4,141,045 to Sheehan, 4,703,465 to Parker and 4,811,325 toSharples, Jr. et al. all disclose various systems for transferringselected sound recordings from a first fixed medium, which, in variousones of the cited references, is alternately disclosed as a record, tapeor CD ROM, to a second fixed medium, a cassette tape, which is then madeavailable for sale to the consumer. As such machines would enable theconsumer to produce a single, high quality, compilation of various soundrecordings not available on a single cassette tape, proper payment ofroyalties owed in connection with the compilation of reproductions ofthe selected sound recordings on a single cassette tape have long been aconcern. For this reason, a number of the audio reproduction devicesdisclosed in the above-cited references are configured to tabulateplaybacks for accounting purposes. None, however, are directed to atrack playback monitoring system specifically configured forincorporation into a CD type audio reproduction device.

It is, therefore, an object of the present invention to provide a CDtype audio reproduction device equipped with a track playback monitoringsystem.

SUMMARY OF THE INVENTION

The present invention is of an apparatus, and an associated method, formonitoring audio track playbacks by an optical disc audio reproductiondevice. An optical disc having at least one audio track encoded thereonis loaded into the optical disc audio reproduction device. A tracknumber corresponding to one of the audio tracks encoded on the opticaldisc is selected using track selection means to initiate playback of theselected audio track by the optical disc audio reproduction device andthe selected track number is stored in a first memory device. A seriesof data signals which define the selected audio track is then read fromthe optical disc by signal detection means and transmitted todemodulation means where audio and non-audio components of the datasignals are separated. The non-audio component of the data signal isthen transmitted to processor means where information identifying theoptical disc is assembled and transmitted to a second memory device. Thecontents of the first and second memory devices are then combined in athird, external, memory device to provide a record of audio trackplaybacks performed by the optical disc audio reproduction device.

In one aspect of the invention, the digital signals transmitted to thedemodulation means is comprised of a plurality of data frames, eachhaving an audio data block and a non-audio subcode block containing asingle Q subcode data bit included therein. The non-audio subcode blockis transmitted to processor means where the single bit of Q data subcodefrom each frame is assembled into a Q data subcode block. The processorthen transmits a portion of the Q data subcode block which identifiesthe optical disc to the second memory device. Preferably, the opticaldisc identifying portion of the Q data subcode block is a UPC code. Atiming circuit then initiates the transfer of the contents of the firstand second memory devices to the third memory device upon detection, bythe demodulation means, of a next frame of data after the portion of theQ data subcode block identifying the optical disc is transmitted to thesecond memory device.

BRIEF DESCRIPTION OF THE DRAWING

The present invention may be better understood, and its numerousobjects, features and advantages will become apparent to those skilledin the art, by reference to the accompanying drawing in which:

FIG. 1 illustrates a single frame of CD data;

FIG. 2 illustrates a Q channel subcode block which is collected from 98frames of CD data and which contains Q subcode data;

FIG. 3A illustrates a first data mode of Q subcode data which may becontained in the Q channel subcode block of FIG. 2 during a lead-in areaof an optical disc;

FIG. 3B illustrates a first data mode of Q subcode data which may becontained in the Q channel subcode block of FIG. 2 during program andlead-out areas of an optical disc;

FIG. 4 illustrates a second data mode of Q subcode data which may becontained in the Q channel subcode block of FIG. 2;

FIG. 5 illustrates a third data mode of Q subcode data which may becontained in the Q channel subcode block of FIG. 2; and

FIG. 6 is a block diagram of a CD player constructed in accordance withthe teachings of the present invention and having a track playbackmonitoring system incorporated therein.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Digital data is encoded onto a compact disc (or "CD") in the form of aseries of pits, each approximately 0.5 μm wide, and lands arranged in atrack, having a pitch of approximately 1.6 μm, which extends in a spiralpath from the inside to the outside of the surface of the CD. Digitaldata encoded on the CD is arranged as a series of frames, eachcontaining 291 data bits.

Referring now to FIG. 1, a frame 10 of CD data may now be seen. At thestart of each frame 10 is a synchronization block 1 containing 27synchronization bits for identifying the start of a new frame 12 of CDdata being transmitted to a CD player. Following the synchronizationblock 12 is an 8 bit subcode block 14 which may contain various types ofinformation regarding the CD being played and which will be more fullydescribed below. The subcode block 14 is followed by a data block 16which may be broken down into a first 96 bit audio data sub-block 18, afirst, or "P", 32 bit parity set 20 used for detecting and correctingerrors due to lost data bits, a second 96 bit audio data sub-block 22and a second, or "Q", 32 bit parity set 24 used for determining whetheran error has occurred. Each 96 bit audio data sub-block 18, 22 may befurther broken down into 12 data bytes, each containing 8 data bits,which alternate between containing audio data for left and rightchannels of the CD player.

Referring next to FIG. 2, the Q channel subcode block will now bedescribed in greater detail. The 8 bit subcode block 14 for a frame 10of CD data includes P, Q, R, S, T, U, V, and W subcode bits. When dataframes read off the CD are eight-to-fourteen (or "EFM") demodulated bythe CD player, the resultant 8 bit subcode block 14 is propagated to asystem microprocessor for the CD player where the P, Q, R, S, T, U, V,and W subcode bits are assembled into corresponding channel subcodeblocks. Of these types of channel subcode blocks, only the P and Qchannel subcode blocks contain audio-related data. The remaining channelsubcode blocks are available for encoding other, non-audio-related,information on an audio CD. For example, so-called CD+G compact discsinclude video information stored in the non-audio-related channelsubcode blocks which may be decoded by an appropriately configureddecoder for display by a monitor or other display means. The non-audiochannel subcode blocks are, however, infrequently used when encodingCDs.

A Q channel subcode block 26 which is assembled by the systemmicroprocessor of a CD player is illustrated in FIG. 2. The Q channelsubcode block 26 includes an "S₀ " synchronization bit 28, an "S₁ "synchronization bit 30, a four bit control block 32, a four bit addressblock 34, a 72 bit Q data block 36 and 16 bit cyclic redundancy checkcode (or "CRCC") block 38. Synchronization bits S₀, S₁ identify thestart of the Q channel subcode block to the system microprocessor. Thefour bit control block 32 handles several CD player functions and isconfigured as set forth in Table I below:

                  TABLE I                                                         ______________________________________                                        Bit 1 = 0         2 Channel                                                   Bit 1 = 1         4 Channel                                                   Bit 2             Undefined                                                   Bit 3 = 0         Copy Deny                                                   Bit 3 = 1         Copy Permit                                                 Bit 4 = 0         Pre-Emphasis OFF                                            Bit 4 = 1         Pre-Emphasis ON                                             ______________________________________                                    

As listed in Table I, bit 1 of the control block 32 indicates the numberof channels used in recording the encoded audio data and instructs theCD player to switch to either a 2 or 4 channel output. Bit 3 of thecontrol block 32 regulates the ability of other digital recorders todigitally record the encoded audio data. Finally, bit 4 of the controlblock indicates pre-emphasis and instructs the CD player to switch tothe appropriate de-emphasis circuit.

The four bit address block 34 indicates which data mode the 72 bit Qdata block 36 is using. An address of 0001 indicates that the Q subcodedata block 36 is Mode 1 Q subcode data, address 0010 indicates Mode 2 Qsubcode data, and address 0011 indicates Mode 3 Q subcode data. Finally,the 16 bit CRCC block 38 is used by the system microprocessor to detecttransmission errors contained in the control, address and Q subcode datablocks 32, 34, 36.

Referring next to FIGS. 3A-B, Mode 1 Q subcode data, which typicallyoccupies at least 9 out of 10 successive subcode blocks, will now bedescribed in greater detail. In its broadest sense, Mode 1 Q subcodedata contains number and start times for tracks and is configureddifferently for the lead-in area of the CD than for the program andlead-out areas of the CD. The configuration of Mode 1 Q data in thelead-in area of the CD is illustrated in FIG. 3A. Mode 1 information iscontained in a table of contents (or "TOC"). The TOC stores dataindicating the number of music selections up to 99 as a track number (or"TNO") and a starting (or "P") time. The TOC is read by the systemmicroprocessor during disc initialization so that the CD player canrespond to any programming or program searching that is requested by theuser. In the lead-in area, an 8 bit TNO field 40 is set to 00,indicating that the data is part of a TOC. The TOC is assembled from an8 bit point field 42 which designates a track number from 0 to 99 and 8bit P minute, P second and P frame fields 44, 46 and 48 which designatean absolute starting time for the designated track number in minutes,seconds and frames, respectively. When the point field 42 is set to A0,the P minute field 44 indicates the number of the first track on thedisc. When the point field 42 is set to A1, the P minute field indicatesthe number of the last track on the disc and when the point field 42 isset to A2, the absolute running time of the start of the lead-out trackis indicated in minutes, seconds and frames by the P minute, P secondand P frame fields 44, 46 and 48. Finally, Mode 1 Q subcode data alsoincludes 8 bit minute, second and frame fields 50, 52 and 54, whichindicate the time through the lead-in track and an 8 bit zero field 56.

Referring next to FIG. 3B, Mode 1 Q subcode data in the program andlead-out areas will now be described in greater detail. In these areas,Mode 1 Q subcode data contains track numbers in an 8 bit TNO field 58,index (or "X") numbers between 01 and 99 within a track in an 8 bitindex field 60, time within a track in 8 bit minute, second and frametime fields 62, 64 and 66 and absolute time for the disc in minute,second and frame absolute time fields 68, 70 and 72 and an 8 bit zerofield 74. In the program area, the TNO field 58 designates individualtracks and, in the lead-out area, is set to AA. Running time is set tozero in the time fields 62, 64 and 66 at the beginning of each track andincreases towards the end of the track. Absolute time is set to zero inthe absolute time fields 68, 70 and 72 at the beginning of the programarea and increases to the start of the lead-out area. The X field 60 isused to both subdivide a track as well as to separate it from asuccessive track. When set to 00, the X field 60 designates a pausebetween tracks and time fields 62, 64 and 66 are used to perform acountdown to the next track. When set to a non-zero value, the X field60 sets index points inside a track. Using the X field 60, up to 99locations within a track can be indexed. Finally, when set to 01, the Xfield 60 designates a lead-out area.

Referring next to FIGS. 4 and 5, Mode 2 and Mode 3 Q subcode data willnow be described in greater detail. When used, Modes 2 and 3 occupy atleast 1 out of 100 successive subcode blocks in the program area andhave identical contents in each block. The configuration of Mode 2 Qsubcode data is illustrated in FIG. 4. Mode 2 Q subcode data includes a52 bit Q data field 76, a 12 bit zero field 78 and an 8 bit absolutetime field 80. The data field 76 contains a catalog number, for example,a UPC bar code, or other unique disc identifying indicia, for the discand the absolute time field 80 continues an absolute time count fromadjacent blocks.

The configuration of Mode 3 Q subcode data is illustrated in FIG. 5.Mode 3 Q subcode data includes a first, 30 bit, data field 82, a first,two bit, zero field 84, a second, 28 bit, data field 86, a second, fourbit, zero field 88 and an 8 bit absolute time field 90. Using 60 bits ofdata per track, the Mode 3 Q subcode data provides ISRC for identifyingeach music track on the disc. More specifically, contained in the first,30 bit, data field 82 are the contents of 5 data bytes. Each of thesedata bytes is comprised of 6 bits of the data field 82 and the two zerobits of the first zero field 84. Of these, bytes 1 and 2 identify thecountry code and bytes 3-5 identify the owner code for the disc.Similarly, the contents of 7 data bytes is contained in the second, 28bit, data field 86. Each of these data bytes is comprised of four bitsof the data field 86 and the 4 zero data bits of the second zero field88. Of these, bytes 6-7 identify the year of the recording and bytes8-12 identify the serial number of the recording. Similar to Mode 2 Qsubcode data, Mode 3 Q subcode data uses the absolute time field 90 tocontinue an absolute time count from adjacent blocks.

Referring next to FIG. 6, an audio reproduction device, for example, anoptical disc reproduction device (or "CD player") 100 constructed inaccordance with the teachings of the present invention and having atrack playback monitoring system incorporated therein shall now bedescribed in greater detail. The CD player 100 includes a pickup andtransport mechanism 102 for reading data encoded on a digital audiomedium having at least one audio track digitally encoded thereon, forexample, an optical disc (or "CD") 104. Specifically, the pickup andtransport mechanism 102 includes a laser diode (or "pickup") assemblymounted on a transport mechanism. The laser diode emits a beam ofinfrared light that strikes against the pits and lands formed on the CD104. When the beam reflects off the pits, less light is reflected into aphotodetector. As a result, the photodetector receives a sequence ofon-off flashes of light which corresponds to the data encoded on the CD104 in a 14 bit code, commonly referred to as "Eight-to-FourteenModulation" or "EFM" signal in which every 8 bits of frame data isencoded on the CD 104 in 14 bits. The EFM signal received by thephotodetector is transmitted to a preamplifier 106 which amplifies thereceived EFM signal and transmits the amplified EFM signal to an EFMdemodulator 108. Additionally, the photodetector also provides trackingand focus error signals which are also propagated to the preamplifier106 for amplification and then transmitted to servo control 109. Inturn, the servo control 109 generates control voltages for operating thetracking and focus coils (not shown) of the pickup and transportmechanism 102.

The EFM demodulator 108 decodes the received EFM signal by detecting thesynchronization bits marking the beginning of each audio frame andstripping the merging bits from the 14 bit code. Each time the EFMdemodulator 108 detects the beginning of an audio frame, the EFMdemodulator 108 transmits a signal to a timing circuit 136 to indicatethat the start of an audio frame has been detected. The EFM demodulator108 then takes the EFM signal and reconverts it to its original 8 bitdigitized format. After demodulation is completed, the EFM demodulator108 then separates the subcode portion of each received frame of datafor transmission to system microprocessor 110. Conversely, the audioportion of each received frame of data is transmitted to digital filter112 where the received audio data is broken down into its left and rightchannel components for respective propagation to D/A converters 114, 116where the received left and right audio components of the digital audiodata are converted into analog audio data by a sample and hold circuit(not shown). Spikes in the left and right analog audio data are removedby low pass filters 118, 120, respectively, and the resultant left andright analog audio signals are then output to audio reproductionequipment (not shown).

When the CD 104 is first inserted into the CD player 100, the CD player100 initializes the disc by reading data encoded on the lead-in area ofthe CD 104 which precedes the tracks. The subcode bits encoded on thelead-in area of the CD 104 are stripped from the input digital signal bythe EFM demodulator 108 and propagated to the system microprocessor 110for assembly into a subcode data block such as that illustrated in FIG.2. During initialization of the CD 104, the Q data subcode blockassembled and processed by the system microprocessor 110 is the lead-inMode 1 Q subcode block illustrated in FIG. 3A. From this block, thesystem microprocessor 110 is provided with information regarding the CD104 such as the number and start times of the tracks on the CD 104 sothat the system microprocessor 110 can respond to various operatorrequests such as program searching where a specific track encoded on theCD 104 is selected for playback. The system microprocessor 110 thenindicates that initialization is complete and that the CD player 100 isready to perform playbacks of tracks encoded on the CD 104 byinstructing front panel indicator means 122 to display the total playingtime of and number of tracks encoded on the CD 104.

Once initialization is complete, the operator may then use the controlsof the CD player 100, for example, the track select means 124 toinstruct the system microprocessor 110 to initiate a playback of aselected track on the CD 104. The system microprocessor 110 will theninstruct the disc spindle servo control 126 to generate a voltage signalwhich will activate spindle motor 128, thereby initiating rotation ofthe CD 104, while using the information regarding the disc 104 providedby the EFM demodulator 108 to instruct the servo control 109 to properlyposition the pickup and transport mechanism 102 to read the selectedtrack from the disc 104. Use of the track select means 124 to select atrack for playback also indicates to the system microprocessor 110 thatit is now permissible to transfer data to a second data register 134 ina manner to be more fully described below. Additionally, if the CDplayer 100 is configured to hold multiple CD's for playback, thecontrols of the CD player 100 may also include disc select means 130which instruct the system microprocessor 110 to shuffle the CDs loadedin the CD player 100 using disc shuttle means (not shown) so that theselected CD will be positioned for initialization and playback.

When, as previously described, the operator of the CD player 100initiates the playback of a selected track from the disc 104 using trackselect means 124, for example, by depressing a number which correspondsto a track on the disc 104 on a numeric keypad, the number identifyingthe selected track is also propagated to a first data register 132 forstorage. As playback of the selected track commences, the EFMdemodulator 108 continues to provide the system microprocessor 110 withQ subcode bits for assembly into Q subcode blocks and subsequentprocessing. As playback of the selected track continues, the systemmicroprocessor 110 will assemble Mode 1, Mode 2 and Mode 3 Q datasubcode blocks such as those illustrated in FIG. 3B, 4 and 5,respectively.

When the system microprocessor 110 assembles a Mode 2 Q data subcodeblock from the subcode bits received from the EFM demodulator 108, thesystem microprocessor 110 will extract disc identifying information suchas a catalog number or UPC bar code, for the CD 104 disc from the datacontained in the data field 76. The extracted catalog number is thentransmitted to a second data register 134 for storage. Upon transmissionof the extracted catalog number to the second data register 134, thesystem microprocessor 110 will not transmit any further data to thesecond data register 134 until instructed by the track select means 124that additional data transfers are acceptable.

Each data register 132, 134 is provided with an output line 142, 140,respectively, connected to a socket-type connector 144 of conventionaldesign, mounted on the exterior surface of the housing of the CD player100 and used to interconnect the data registers 132, 134 with anexternal storage device 138, for example, a tape or disk drive. Theexternal storage device 138 has first and second input lines 146, 148,respectively, connected to a plug-type connector 150 of conventionaldesign. When the plug-type connector 150 is inserted in the socket-typeconnector 144, line 140 is interconnected with line 146 and line 142 isinterconnected with line 148, thereby connecting the external storagedevice 138 with the first and second data registers 132, 134.

When the system microprocessor 110 transmits the disc identifyinginformation to the second data register 134, the system microprocessor110 also transmits an indication that the disc identifying informationhas been transferred to the timing circuit 136. When the timing circuit136 receives, from the EFM demodulator 108, an indication that a nextframe of data has been transmitted to the EFM demodulator 108 after thedisc identifying information has been stored in the second data register134, the timing circuit 136 will initiate the propagation of thecontents of the data registers 132, 134 to external storage device 138.Preferably, the timing circuit will first instruct the second dataregister 134 to transfer the disc identifying information stored in thesecond data register 134 to the external storage device 138 andsubsequently instruct the first data register 132 to transfer the tracknumber selected for playback stored in the first data register 132.Preferably, the timing circuit 136 is constructed of combinatorial logicconfigured in a manner to provide, in succession, the desired outputsignals to the data registers 134, 132 upon receiving the aforementionedinput signals from the system microprocessor 110 and the EFM demodulator108.

When received by the external storage device 138, the contents of thefirst data register 132 is appended to the contents of the second dataregister 134 to form a single data block which uniquely identifies theCD track selected for playback by the CD player 100. As successivetracks are selected for playback using the track select means 124, thestorage device 138 will accumulate data blocks identifying each CD trackselected for playback. This data may be accessed at any time to monitorthe selected playbacks in connection with royalty calculations or othermanagement functions.

Thus, there has been described and illustrated herein a CD playerconfigured to monitor the CD tracks selected for playback and toaccumulate data which uniquely identifies each selected CD track foroutput to an external storage device. Those skilled in the art, however,will recognize that many modifications and variations besides thosespecifically mentioned may be made in the techniques described hereinwithout departing substantially from the concept of the presentinvention. For example, it is contemplated that the present inventionmay be readily adapted to monitor the tracks selected for playback froma digital audio tape recording (or "DATR"). Accordingly, it should beclearly understood that the form of the invention as described herein isexemplary only and is not intended as a limitation of the scope of theinvention.

What is claimed is:
 1. Apparatus for reproducing audio signals encodedon optical discs as audio tracks and monitoring playbacks of said audiotracks encoded on said optical discs by said apparatus,comprising:signal detection means for detecting data signals encoded onan optical disc as a collection of numbered audio tracks, said encodeddata signals corresponding to each of said audio tracks having an audiodata component and a non-audio data component which contains informationidentifying said optical disc; track selection means for selecting oneof said audio tracks encoded on said optical disc for playback; firstmemory means electrically connected to said track selection means, saidfirst memory means storing a number corresponding to said audio trackselected with said track selection means; servo control meanselectrically connected to said track selection means, said servo controlmeans positioning said signal detection means and rotating said opticaldisc in response to selection of one of said audio tracks by said trackselection means such that said signal detection means reads said encodeddata signals corresponding to said selected audio track; demodulationmeans for separating said audio and non-audio data components of saidencoded data signal detected by said signal detection means; secondmemory means for storing said information identifying said optical disccontained in said non-audio data component; said audio data componentseparated by said demodulation means being transmittable to a soundsystem for audible reproduction of said selected audio track and saidinformation identifying said optical disc contained in said non-audiodata component separated by said demodulation means being transmitted tosaid second memory means; and third memory means for storing, for eachoptical disc track selected by said track selection means, said numberstored in said first memory means by said track selection means and saidinformation identifying said optical disc stored in said second memorymeans by said demodulation means.
 2. An apparatus for reproducing audiosignals and monitoring audio track playbacks according to claim 1wherein each of said audio tracks encoded on said optical disc anddetected by said signal detection means is comprised of a plurality ofdata frames, each said frame of data comprised of an audio data blockand at least one non-audio data bit, and further comprising processormeans, connected to said demodulation means, for assembling said atleast one non-audio data bit for successive data frames into a non-audiodata block containing said information identifying said optical disc. 3.An apparatus for reproducing audio signals and monitoring audio trackplaybacks according to claim 2 wherein a first portion of said non-audiodata block contains said information identifying said optical disc andwherein said processor means further comprises means for transmittingonly said first portion of said non-audio block to said second memorymeans.
 4. An apparatus for reproducing audio signals and monitoringaudio track playbacks according to claim 2 wherein said frame of data iscomprised of an audio data block and one Q subcode data bit and whereinsaid processor means further comprises means for assembling said one Qsubcode data bit from each frame of data into a Q subcode data block. 5.An apparatus for reproducing audio signals and monitoring audio trackplaybacks according to claim 4 wherein said processor means furthercomprises:means for extracting a UPC code for said optical disc fromsaid Q subcode data block; and means for transmitting said extracted UPCcode identifying said optical disc to said second memory means.
 6. Anapparatus for reproducing audio signals and monitoring audio trackplaybacks according to claim 5 and further comprising a timing circuitfor clocking the contents of said first and second memory means intosaid third memory means upon propagation of a next data frame to saiddemodulation means after storage of said number corresponding to saidselected audio track in said first memory means and storage of saidextracted UPC code identifying said optical disc in said second memorymeans.
 7. An apparatus for reproducing audio signals and monitoringaudio track playbacks according to claim 6 wherein said third storagemeans further comprises means for assembling said extracted UPC codereceived from said second memory means and said number corresponding tosaid selected audio track received from said first memory means into adata block which identifies each audio track selected for playback usingsaid optical disc audio reproduction system.
 8. Apparatus forreproducing audio signals encoded on optical discs as audio tracks andmonitoring playbacks of said audio tracks encoded on said optical discsby said apparatus, comprising:signal detection means for detecting datasignals encoded on an optical disc as a collection of numbered audiotracks, each said audio track comprised of a plurality of data framesand each said frame of data comprised of an audio data block and atleast one non-audio data bit; track selection means for selecting one ofsaid audio tracks encoded on said optical disc for playback; firstmemory means having an input electrically connected to said trackselection means and an output, said first memory means storing a numbercorresponding to said audio track selected with said track selectionmeans; processor means having first and second inputs and first andsecond outputs, said first input electrically connected to said trackselection means for receiving said number corresponding to said audiotrack selected thereby; servo control means electrically connected tosaid first output of said processor means, said servo control meanscontrolling the positioning of said signal detection means and therotating of said optical disc in response to selection of one of saidaudio tracks by said track selection means such that said signaldetection means reads said encoded data signals corresponding to saidselected audio track; demodulation means for separating said audio andnon-audio data components of said encoded data signal detected by saidsignal detection means, said audio data component separated by saiddemodulation means being transmittable to a sound system for audiblereproduction of said selected audio track; said processor means furthercomprising means for assembling said at least one non-audio data bit forsuccessive data frames into a non-audio data block containing saidinformation identifying said optical disc; second memory means having aninput connected to a first output of said processor means and an output,said information identifying said optical disc contained in saidassembled non-audio data block being transmitted to said second memorymeans; and a connector socket plug having first and second contactsconnected to said outputs of said first and second memory means,respectively; a timing circuit for clocking the contents of said firstand second memory means to said first and second inputs of saidconnector plug upon detection, by said demodulation means, of a nextdata frame after storage of said number corresponding to said selectedaudio track in said first memory means and storage of said non-audiodata block identifying said optical disc in said second memory means;wherein an external storage device having connector plug meansinsertably mounted in said connector socket will receive the contents ofsaid first and second memory means for storage therein, thereby provinga record of audio tracks playbacks performed by said optical disc audioreproduction device.
 9. An apparatus for reproducing audio signals andmonitoring audio track playbacks according to claim 8 wherein said frameof data is comprised of an audio data block and one Q subcode data bitand wherein said processor means further comprises means for assemblingsaid one Q subcode data bit from each frame of data into a Q subcodedata block.
 10. An apparatus for reproducing audio signals andmonitoring audio track playbacks according to claim 9 wherein saidprocessor means further comprises:means for extracting a UPC code forsaid optical disc from said Q subcode data block; and means fortransmitting said extracted UPC code identifying said optical disc tosaid second memory means.
 11. A method for monitoring audio trackplaybacks by an optical disc audio reproduction device, comprising thesteps of:loading an optical disc having at least one audio track encodedthereon into an optical disc audio reproduction device, each said audiotrack having a track number assigned thereto; selecting a track numbercorresponding to one of said audio tracks encoded on said optical discto initiate playback of said selected audio track by said optical discaudio reproduction device; storing said track number in a first memorydevice; reading said selected audio track from said optical disc, saidselected audio track having a non-audio code incorporated therein foridentifying said optical disc; storing said non-audio code read fromsaid selected audio track in a second memory device; combining, in athird memory device, said track number and said non-audio optical discidentification code to provide a record of audio track playbacksperformed by said optical disc audio reproduction device.
 12. A methodfor monitoring audio track playbacks by an optical disc audioreproduction device according to claim 11 wherein the step of readingsaid selected audio track from said optical disc further comprises thesteps of:optically detecting a pattern of pits and lands formed on saidoptical disc, said series of pits and lands comprising said selectedaudio track; producing a digital signal corresponding to said pattern ofdetected pits and lands; and separating said digital signal into anaudio portion for transmission to sound generation equipment and anon-audio portion for transmission to a processor, said non-audioportion of said digital signal containing said non-audio codeidentifying said optical disc.
 13. A method for monitoring audio trackplaybacks by an optical disc audio reproduction device according toclaim 12 wherein said digital signal is comprised of a plurality of dataframes, each said data frame having an audio data block and a non-audiosubcode block having a single Q data bit, and further comprising thesteps of:assembling said single Q data bit from each frame into a Q datasubcode block; and separating said non-audio code identifying saidoptical disc from said Q data subcode block.
 14. A method for monitoringaudio track playbacks by an optical disc audio reproduction deviceaccording to claim 13 wherein said non-audio code identifying saidoptical disc in said Q data subcode block is a UPC code.
 15. A methodfor monitoring audio track playbacks by an optical disc audioreproduction device according to claim 13 and further comprising thesteps of:transmitting said track number stored in said first memorydevice and said non-audio Q data subcode identifying said optical discstored in said second memory device to said third memory device upontransmission of a next data frame for separation into audio andnon-audio data blocks.
 16. A method for monitoring audio track playbacksby an optical disc audio reproduction device according to claim 15 andfurther comprising the step of transmitting, in sequence, said non-audioQ data subcode identifying said optical disc stored in said secondmemory device, followed by said track number stored in said first memorydevice, to said third memory device.
 17. A method for monitoring audiotrack playbacks by an optical disc audio reproduction device accordingto claim 16 wherein said non-audio code identifying said optical disc insaid Q data subcode block is a UPC code.
 18. A method for monitoringaudio track playbacks by an audio reproduction device, comprising thesteps of:loading a digital audio medium having at least one audio trackdigitally encoded thereon into an audio reproduction device, each saidaudio track having a track number assigned thereto; selecting a tracknumber corresponding to one of said audio tracks encoded on said digitalaudio medium to initiate playback of said selected audio track by saidaudio reproduction device; storing said track number in a first memorydevice; reading said selected audio track from said digital audiomedium, said selected audio track having a non-audio code incorporatedtherein for identifying said digital audio medium; selected audio trackin a second memory device; combining, in a third memory device, saidtrack number and said non-audio digital audio medium identification codeto provide a record of audio track playbacks performed by said audioreproduction device.
 19. A method for monitoring audio track playbacksby an audio reproduction device according to claim 18 wherein the stepof reading said selected audio track from said digital audio mediumfurther comprises the steps of:producing a digital signal correspondingto said digitally encoded audio track; and separating said digitalsignal into an audio portion for transmission to sound generationequipment and a non-audio portion for transmission to a processor, saidnon-audio portion of said digital signal containing said non-audio codeidentifying said digital audio medium.